Illinois State University Exercise and Pregnancy What are the common responses and adaptations we see in the pregnant exerciser?

Illinois State UniversityIllinois State University

Exercise and Pregnancy

What are the common responses and adaptations we see in the

pregnant exerciser?



Cardiovascular system:

Cardiac outputCardiac output– rapid increase in 1st rapid increase in 1st

two trimesterstwo trimesters

– levels off in 3rdlevels off in 3rd

– 30-50% above normal30-50% above normal

– increased stroke increased stroke volumevolume

– greater strain on heart greater strain on heart during exerciseduring exercise



Blood flow distributionBlood flow distribution– increased flow to surfaceincreased flow to surface– increased renal, pulmonary, and uterine blood increased renal, pulmonary, and uterine blood

flowflow– decreased total peripheral resistance and decreased total peripheral resistance and

increased peripheral blood flowincreased peripheral blood flow– decreased venous returndecreased venous return– exercise helps with venous returnexercise helps with venous return



Blood pressureBlood pressure– decreased SBP and DBP during 1st two decreased SBP and DBP during 1st two

trimesterstrimesters



Blood volumeBlood volume– increases 50% by end increases 50% by end

of 2nd trimesterof 2nd trimester

– increased plasma increased plasma volumevolume


Pulmonary System

Diaphragm elevatesDiaphragm elevates– FRC decreases by 25% due to decreased ERV FRC decreases by 25% due to decreased ERV

and RVand RV– hyperventilation occurs at rest due to increased hyperventilation occurs at rest due to increased

progesterone levels and changes in the progesterone levels and changes in the threshold of the respiratory centers.threshold of the respiratory centers.


Metabolic System:

Slight increase in blood acidosisSlight increase in blood acidosis

Increase in resting VOIncrease in resting VO22 and VCO and VCO22


Metabolic System:

Metabolic rate is increasedMetabolic rate is increased Increased use of carbohydrates as fuelIncreased use of carbohydrates as fuel resultresult

– increased VOincreased VO22 at any given workload at any given workload

– increased Oincreased O22 debt (EPOC) debt (EPOC)


Musculoskeletal System:

Increased joint laxity (relaxin)Increased joint laxity (relaxin) Stretching and thinning of abdominal wallStretching and thinning of abdominal wall


Musculoskeletal System:

Forward shift in c of g and anterior rotation Forward shift in c of g and anterior rotation of pelvisof pelvis

Proprioception and coordination are Proprioception and coordination are adversely effectedadversely effected


Benefits of Exercise to the Pregnant Woman

1. Facilitate a general feeling of well-being.1. Facilitate a general feeling of well-being. 2. Control of body composition.2. Control of body composition. 3. Maintenance or development of optimal 3. Maintenance or development of optimal

posture.posture. 4. Decrease in the minor discomforts of 4. Decrease in the minor discomforts of

pregnancy.pregnancy. 5. Promotes pelvic floor strength.5. Promotes pelvic floor strength.



6. Maintain or improve aerobic 6. Maintain or improve aerobic conditioning.conditioning.

7. Maintain or improve strength and/or 7. Maintain or improve strength and/or flexibility.flexibility.

8. Facilitate general recovery after delivery.8. Facilitate general recovery after delivery.– Decrease by 1/2 post partum recovery days.Decrease by 1/2 post partum recovery days.

9. Improved tolerance during delivery.9. Improved tolerance during delivery.



10. Improved physiologic adaptations to 10. Improved physiologic adaptations to pregnancy.pregnancy.

11. Improved ability to dissipate heat.11. Improved ability to dissipate heat. 12. Limits the pregnancy related increase in 12. Limits the pregnancy related increase in

peripheral insulin resistance.peripheral insulin resistance.


Risks to the Mother:

1. Risks of injury due to overuse.1. Risks of injury due to overuse. 2. Increased potential for fatigue.2. Increased potential for fatigue. 3. Joint injury.3. Joint injury. 4. Redistribution of cardiac output.4. Redistribution of cardiac output. 5. Thermoregulatory problems.5. Thermoregulatory problems.


Latest Research

Most women increase body mass by 20% Most women increase body mass by 20% during pregnancy.during pregnancy.


Latest Research

Supine exercise doesn’t create abdominal Supine exercise doesn’t create abdominal hernias.hernias.– Abdominal recover within 6 weeks.Abdominal recover within 6 weeks.


Latest Research

Cardiac remodeling occurs. Cardiac remodeling occurs. – VO2 Max higher 10-40 weeks post-partum.VO2 Max higher 10-40 weeks post-partum.


Latest Research

Birth occurs 5-7 days earlier.Birth occurs 5-7 days earlier.– No increased incidence of premature birth.No increased incidence of premature birth.


Latest Research

Higher rate of normal delivery.Higher rate of normal delivery.– Quicker recovery post-partum.Quicker recovery post-partum.


Latest Research

Decreased feelings of stress.Decreased feelings of stress.


Latest Research

Increased fitness and muscle tone.Increased fitness and muscle tone.


Latest Research

Improved bladder control.Improved bladder control.


Risks to the Baby:A. Heat Stress:A. Heat Stress: 1. Heat stress and malformation (animal 1. Heat stress and malformation (animal

studies).studies). 2. Heat stress and malformation in saunas in 2. Heat stress and malformation in saunas in

humans during early pregnancy.humans during early pregnancy.


Risks to the Baby:

3. With exercise there is an increase in skin 3. With exercise there is an increase in skin temperature with minor increases in temperature with minor increases in

core core temperature.temperature.

4. Exercising studies have not shown the 4. Exercising studies have not shown the correlation between heat stress and correlation between heat stress and malformation.malformation.


Risks to the Baby:

B. Oxygen Delivery:B. Oxygen Delivery: 1. Animal studies show conflicting results.1. Animal studies show conflicting results.

2. Body can adapt to make-up for decreased 2. Body can adapt to make-up for decreased blood flow - increase hemoconcentration blood flow - increase hemoconcentration and better extraction.and better extraction.


Risks to the Baby:

C. Fetal Heart Rate Changes:C. Fetal Heart Rate Changes: 1. Conflicting results.1. Conflicting results.

2. Increased HR during start of exercise 2. Increased HR during start of exercise then it levels off.then it levels off.


Risks to the Baby:

3. No adverse effects.3. No adverse effects.

4. Trained women show less uterine blood 4. Trained women show less uterine blood flow.flow.


Risks to the Baby:

D. Decreased Blood Flow:D. Decreased Blood Flow: 1. Animals suggest there is a relationship 1. Animals suggest there is a relationship

between between exercise and low birth weight.exercise and low birth weight.


Risks to the Baby:

2. This does not seem to be a problem in 2. This does not seem to be a problem in rationally trained women.rationally trained women.

3. No relationship between exercise and 3. No relationship between exercise and miscarriage.miscarriage.


Guidelines for Exercise

1. Medical and exercise history of the 1. Medical and exercise history of the individual.individual.

2. Questions or unusual symptoms2. Questions or unusual symptoms– bleeding, bleeding, dizziness, dizziness, – cramping, cramping, joint pain joint pain– faintness, faintness, elevated blood pressure, elevated blood pressure, – STOP exercising and consult physician.STOP exercising and consult physician.



3. Listen to your body.3. Listen to your body.

4. Expect some discomfort.4. Expect some discomfort.



5. Exercise regularly.5. Exercise regularly.

6. Do not exercise vigorously in hot humid 6. Do not exercise vigorously in hot humid weather.weather.



7. Do not exercise at all during an illness 7. Do not exercise at all during an illness with fever.with fever.



8. Avoid high impact activities.8. Avoid high impact activities.

9. Drink plenty of fluids.9. Drink plenty of fluids.



10. Rise slowly from down positions.10. Rise slowly from down positions.

11. ACOG recommends that the HR not 11. ACOG recommends that the HR not exceed 140 bpm.exceed 140 bpm.



12. Avoid the valsalva maneuver.12. Avoid the valsalva maneuver.



13. Do not begin a new fitness program.13. Do not begin a new fitness program.

14. Follow basic fitness principles.14. Follow basic fitness principles.


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Illinois State University Exercise and Pregnancy What are the common responses and adaptations we see in the pregnant exerciser?